When the saw chain of motor powered saws shall be tensioned, various tools conventionally need to be used for easing the clamping force which the side cover, which normally consists of the so called clutch cover, exerts on the rear portion of the guide bar, in order thereafter to be able to tension the chain and secure it in a new position. Moreover, the chain tensioner usually is difficult to access and/or is very dirty. All this makes the chain tension cumbersome. This is an important disadvantage of existing motor chain saws and this is particularly true for motor chain saws intended for sawing in rock and concrete, because the saw chains used for such motor saws often need to be tensioned, as cuttings get in between links of the chain and cause wear of the rivets.